1. Field of the Invention
The present invention relates to a method for operating a turbocompressor. Furthermore, it also relates to a device for carrying out this method.
2. Discussion of Background
In more recent times, gas turbines with a high pressure ratio have been coming into use for stationary applications. They are advantageously equipped with intercooling during compression, in order in this way to achieve additional improvements in service performance and efficiency. This is achieved in a known way when the outlet temperature of the compressed combustion air resulting from the work of compression is reduced in the cooler. To be specific, excessively high compressor outlet temperatures cause problems in cooling the gas turbine and with respect to the polluting NO.sub.x emissions.
On the other hand, the effectiveness of the provided cooler depends on the temperature level to which the combustion air fed to it can be cooled. This temperature level is determined chiefly by the available coolant. Water or condensate, which forms a closed cooling circuit with the cooler, as a rule, is generally used as coolant. The provision of an artificial heat sink is frequently required in order to achieve a sufficient temperature drop in the combustion air. Such an artificial heat sink can be a cooling tower or a convective air cooler. Dt is known, however, that cooling water is available in sufficient quantity and quality only in the rarest instances.
Since, however, there is only a very sluggish heat transfer to the environment even in cooling towers which operate according to the evaporation principle or in air coolers in which convective heat transfer takes place, there is a need for correspondingly large structures. By and large, the space required for structures as large as this is not present at the installation site of a gas turbine. Moreover, convective coolers and compact, forced-ventilated evaporative coolers require electric energy in order to drive the fans thereby necessary.
In order to solve this basic problem, measures for a very compact transfer of heat to the environment have been found, in which a spontaneous evaporation of hot pressurized water takes place, for example in the flash method, instead of a sluggish evaporation, more specifically, instead of evaporation under partial pressure.
Thus, for example, it is possible to generate in the intercooler of a gas turbine or of a compressor hot water of, for example, 200.degree. C. at a pressure which is above the respective saturation pressure, here 16 bar, for example.
The water heated in this way is depressurized to ambient pressure, a spontaneous evaporation of a partial quantity of water taking place. In this process, the hot pressurized water loses as much thermal energy as its heat content exceeds that of water at a temperature of 100.degree. C. Of course, the quantity of evaporated water must be replaced by corresponding make-up water.
It is disadvantageous in such a cooling device that because of the ambient pressure of approximately 1 bar the water can be cooled only to approximately 100.degree. C.